The role of endogenous cholecystokinin (CCK) in the regulation of gastric emptying remains controversial. We therefore studied the effect of the CCK-A receptor antagonist loxiglumide on gastric emptying of a high-caloric solid-liquid meal in humans. Gastric emptying was assessed in eight volunteers using intravenous loxiglumide or placebo in a randomized double-blind order. Subjects were studied by a dual-headed gamma camera after ingestion of a pancake (570 kcal) labeled with 99mTc-sulfur colloid and 500 ml 10% glucose containing 111In-diethylenetriamine pentaacetic acid. Plasma CCK was measured by a specific radioimmunoassay. Loxiglumide markedly accelerated gastric emptying of both phases of the meal. The lag period was shortened by 26% (P &lt; 0.03); the area under the emptying curve and half-emptying time of solid emptying were lowered by 19 and 24% (P &lt; 0.02) and of liquid emptying by 18 and 24% (P &lt; 0.04), respectively. Plasma CCK levels were higher during infusion of loxiglumide compared with placebo (P &lt; 0.02). These data demonstrate that post-prandially released CCK is a major regulator of gastric emptying of physiological meals containing both solid and liquid components.